1. Field of the Invention
The present invention relates to a suspension device in a vehicle such as an automobile, and more particularly to an improvement of the suspension device for a steering vehicle wheel with respect to the stability of the vehicle in the running turn.
2. Description of the Prior Art
As described in, for example, Japanese Utility Model Laid-open Publication 61-129606, there is known as a type of the suspension device for a steering vehicle wheel in a vehicle such as an automobile a suspension device which comprises a carrier for supporting the vehicle wheel to be rotatable about an axis of rotation, and a lower arm pivotably connected with said carrier at an outboard end thereof and pivotably connected with a vehicle body at two inboard end portions thereof spaced from one another in a substantially longitudinal direction of the vehicle via rubber bushes, wherein the rear side mounting point of the lower arm is pushed outboard in the braking of the vehicle by utilizing a hydraulic pressure available for operating the braking system of the vehicle.
In this suspension device, as the rear side mounting point of the lower arm is pushed outboard in the braking of the vehicle, the lower arm is turned about the forward mounting point thereof so as to shift the vehicle wheel in the direction of toeing in, so that the shifting of a vehicle wheel in the direction of toeing out during braking of the vehicle due to a turning of the lower arm under a compression of the rubber bushes is decreased or cancelled thus improving the stability of the vehicle in running straight forward while braking.
However, in the suspension device of the above-mentioned construction no improvement of the stability of the vehicle is yet available in the running turn of the vehicle. As well known in the art, it is desirable from the view point of improving the stability of the vehicle in the running turn that the king pin offset is small. However, in the suspension device of the above-mentioned construction, the king pin offset is not decreased when the vehicle turns during braking. Therefore, the stability of the vehicle in the running turn during braking is not improved in relation with the king pin offset.
It would be contemplated in the suspension device of the above-mentioned construction to positively bias the lower arm about the front mounting point thereof in the direction of toeing in the vehicle wheel in the running turn of the vehicle. In such a modification, however, the lower arms for the left and right vehicle wheels are all biased in the direction of toeing in the vehicle wheels. Therefore, in the vehicle wheel at the outside of the turn, the king pin offset is decreased. However, in the vehicle wheel at the inside of the turn, the king pin offset is increased. This would deteriorate the stability of the vehicle in the running turn, particularly in the transition thereto and therefrom.